Most northern cities incur considerable yearly expense in the removal of snow and ice from streets and other outdoor surfaces to meet the winter time needs of business, industry, and the public in general. Reliance on mechanical means of snow or ice removal alone, however, is insufficient, necessitating the use of deicing salts. Rock salt or sodium chloride is the most common chemical used for deicing, primarily because of its low cost, ease of transportation, and readily dispersible form.
The cost of the prior art deicing salts, including sodium chloride, calcium chloride, magnesium chloride, or rock salt, are deceptively low given the unassumed cost of corrosion to metal guardrails, bridge supports, metal concrete reinforcing rods and automobiles. As such, these chemicals ultimately cost the consuming public far more in corrosion damage than the initial material cost would indicate. In order to overcome these corrosive properties, chemicals such as ammonium sulfate, ammonium nitrate, ammonium chloride, urea, alcohols and glycols have been tested as replacements for the corrosive salts. While these chemicals reduce corrosion, they are more expensive, difficult to apply and carry hidden costs in the form of environmental pollution and toxic properties.
In searching for chemicals that can be used to melt ice and snow without causing corrosion or pollution, the preferable chemicals should have suitable water solubility, be inexpensive to produce on an industrial scale and be applicable by generally known means and equipment. For these reasons, many deicing compositions have been proposed that contain protein from food, beverage or agricultural waste streams. For example, deicing compositions have been proposed that contain byproducts from the production of cheese and milks, waste concentrates from the alcohol distilling industry, byproducts of sulfite pulp mills, solubles that settle during the fermentation of wines, and the like. These compositions also contain corrosive salts but the protein sources appear to reduce the corrosive effects of the salts while maintaining the ice- and snow-melting properties. Additionally, the protein components reduce the need for additional corrosion inhibitors in the deicing compositions. Unfortunately, the addition of proteins to deicing solutions causes many problems with handling and stability characteristics of the solutions. Typically, the protein sources are difficult, if not impossible to get fully mixed with the other components of the deicing compositions. Further, any deicing composition that is made containing a protein component often forms precipitates and/or flocculates during storage prior to use and during use as well. If the proteins do not come completely out of solution to form a precipitate or flocculate, they still often form gels that cause gelling of the deicing composition and impair the ability to evenly apply and distribute the deicing compositions.
Thus, there exists a need for protein-containing deicing compositions with good handling and anticorrosive properties that maintain the ability to melt snow and ice from outdoor surfaces.